The return of airships... again.

Flip through an old stack of future-philic magazines such as my longtime favorite, Popular Science, you’ll find proclamations of a new era of air ships announced every few years. I’m not one to blame them for this sort of over zealous optimism. The appeal of zeppelins is enduring, and difficult to describe. Is it their slow moving grace, like whales in the sky? The retro-hip 1930s futurama look and feel of the modern, when modern really meant something?

Today, I’d add one more thought to this list of indefinable appeals: energy efficiency. Using the uplift of ultra light gases, rather than the airfoil effect of plane wings, hot air balloons and zeppelins can rise into the air with less kinetic force than planes or helicopters and thus promise to make air travel less energy intensive and costly. In a period of rising energy prices and growing anxiety over whether airlines will be crushed by carbon pricing, there may even be fresh economic appeal in a new generation of airships.

As if on cue, Popular Mechanics this month rolled out a review of four current airship projects, all of which mix new era technological goodies with old-school zeppelin design to revive, once again, the promise of city skies filled with airships. Rather than venting helium to cut its buoyancy, for instance, the Aeroscraft ML866 (pictured above), compresses and decompresses helium onboard to change its lift for landing and takeoff. This conserves the lighter-than-air gas, permitting longer flights and cutting costs. Another neat design mounts thin film solar cells on its curved top, so as to harvest electricity from the sun at high altitudes to power electric propellers.

Before it's here, it's on the Bloomberg Terminal.